1. Field of the Invention
The invention relates to a process and apparatus for manufacturing mouldings of plastic material, in which the plastic material is introduced by a dispensing device into a mould cavity of a tool comprising a basic part and several mobile parts and is retained in the mould cavity until adequate stability of shape is attained, whereupon the moulding is ejected.
2. Description of the Prior Art
In a known method and a device suitable for carrying out the latter in accordance with DE-B-11 45 786, for the manufacturing of plastic parts, there are associated with a basic part of the tool several mobile tool parts which are fixedly arranged on a rotatable table plate. The table plate is turned gradually, so that the mobile tool parts are connected successively with the basic tool part and plastic material can be injected into the corresponding mould cavities. It is a disadvantage that in this method and the known device, the cycle time on even the mobile tool parts at a distance from the basic tool part is dependent on the cycle time for the manufacture of the moulding.
It is already known to use so-called mould carousels for the purpose of manufacturing plastic moulding which require a longer cycle time between the introduction of the liquid plastic material into the mould cavity and the removal of the moulding. The carousels usually comprise a turntable on which a plurality of moulds are disposed one behind the other around the periphery thereof at equal angular distances apart. The mould located opposite the dispensing device is filled with plastic material, whereupon the turntable is rotated through a further angular spacing, so that the next mould may be filled with liquid plastic material. In the meantime, the mould is opened in the region of the other moulders, the moulding is removed, and the mould cavity is cleaned and recoated with a parting agent. Processes and installations of this kind are widely used, although the costs of manufacturing a large number of complete moulds is relatively high, and the spatial requirements are also relatively high if several working operations are to be performed in succession.